Integrated vessel ligator and transector

ABSTRACT

Surgical treatment of tissue includes electrocauterization of blood vessels interposed between spaced sets of electrodes of opposite polarity, and includes transection of such tissue by a cutter that is mounted between the spaced sets of electrodes for translational and lateral movement relative to the sets of electrodes. Orientations of the sets of electrodes within a range of angles about an elongated axis of a supporting body are controlled by manual movement of an actuator mounted near a proximal end of the body for movement through a smaller range of angles via linkage connecting the actuator to the electrodes. Tissue dissection with gas insufflation to form an anatomical space in tissue is facilitated by a fluid outlet port located near the tissue-dissecting tip at the distal end of the elongated body that delivers through the tissue-dissecting tip to the dissected tissue a fluid under pressure that is supplied along a lumen within the elongated body.

RELATED APPLICATIONS

This application is a continuation-in-part of application Ser. No.10/455,942 entitled “Dissection and Welding of Tissue”, filed on Jun. 6,2003 now U.S. Pat. No. 7,534,243 by Albert K. Chin, et al., which is acontinuation-in-part of application Ser. No. 10/054,477 entitled “VesselHarvesting Apparatus And Method”, filed on Jan. 18, 2002 now U.S. Pat.No. 7,485,092 by M. Stewart, et al., which is a continuation-in-part ofapplication Ser. No. 09/413,012 entitled “Tissue Dissector Apparatus andMethod”, filed on Oct. 5, 1999 by Albert K. Chin, which is acontinuation of application Ser. No. 09/133,136 entitled “TissueDissector Apparatus And Method”, filed on Aug. 12, 1998 by Albert K.Chin, now abandoned.

FIELD OF THE INVENTION

This invention relates to tissue transectors, and more particularly tosuch devices having electrocautery electrodes disposed for selectivecauterization and captivating of tissue structures such as blood vesselsduring surgical procedures to hemostatically seal and transect thevessels.

BACKGROUND OF THE INVENTION

Endoscopic surgery commonly requires manual manipulation of surgicalinstruments that are introduced into a surgical site within a patientthrough elongated cannulas containing one or more interior lumens ofslender cross section. Endoscopic surgery to harvest a vessel such asthe saphenous vein or the radial artery usually involves an elongatedcannula that is advanced along the course of the vein from an initialincision to form an anatomical space about the vein as connective tissueis dissected away from the vein.

Lateral branch vessels of the saphenous vein can be convenientlyisolated and ligated within the anatomical space under endoscopicvisualization using surgical scissors that can be positioned andmanipulated through the elongated cannula. Such surgical procedures arecommonly employed in the preparation of the saphenous vein for removalfrom within the anatomical space for use, for example, as a shunting orgraft vessel in coronary bypass surgery.

Surgical scissors that are used to transect vessels within the confinesof limited anatomical space formed along the course of the saphenousvein commonly incorporate electrodes on or near the tissue-shearingblades. Scissors of this type are suitable for monopolar or bipolarelectrocauterization of tissue prior to transection of, for example,lateral side branches of the saphenous vein to be harvested. However,placement of the electrodes in relation to the tissue-shearing edges ofthe scissor blades may inhibit proper operation of the scissor blades toshear tissue and may inhibit thorough electrocauterization of a sidebranch vessel as the scissor blades close during transection of thevessel.

Additionally, the scissor blades are conventionally rotated about acommon pivot axis at the distal end of an elongated body using actuatinglevers within confined dimensions to preserve the diminutive sectionalarea of the scissors suitable for passage through a lumen of anelongated cannula. The associated linkage to a manual actuator at theproximal end of the elongated body commonly establishes littlemechanical advantage sufficient for remotely shearing tissue undercontrol of the proximal actuator, with resultant jamming of the scissorblades or other impediments to orderly surgical procedures.Additionally, repeated opening and closing of the scissor blades is atedious procedure required to slice tissue along an extended path.

Subcutaneous tissue-dissecting procedures are commonly performed undervisualization through an endoscope that is positioned within a cannulaand that is protected from directly contacting the tissue by a taperedtransparent tip that performs the dissection as the assembly is advancedthrough tissue. The dissected tissue may also be dilated by insufflatingthe anatomical space formed in the dissected tissue using gas underpressure that is supplied to the dissected anatomical space, usuallythrough an access port located at the initial cutaneous incision wheretissue dissection begins. However, visualization through the transparenttip of the tissue being dissected is commonly obscured by tissue andbodily fluids that contact the tip. In addition, insufflating ananatomical space via gas introduced under pressure through the accessport becomes more problematic as the anatomical space is extendedremotely from the access port and the dissected tissue surrounds thedissecting instrument. It would be desirable to overcome remotetissue-cutting difficulties, and to provide reliable visualizationthrough a transparent tip during tissue dissection to form an anatomicalspace in tissue while under insufflation.

SUMMARY OF THE INVENTION

In accordance with the illustrated embodiment of the present invention,a tissue transector includes a pair of yoke-like electrodes mounted inspaced, substantially parallel relationship at the distal end of aslender, flexible body for manual extension and rotational orientationunder control of a lever mounted at the proximal end of the slenderbody. The electrodes are positioned to supply electrical energy from anexternal source to cauterize tissue positioned between the yokes priorto shearing the cauterized tissue via a slicing blade at a remotesurgical site in a patient. The transector may be angularly positionedabout the elongated axis of the body to orient the yoke-like electrodesfor effective electrocauterization of the tissue to be sheared within awide range of angular orientations about the elongated axis of the body.In one embodiment, the slicing blade is interposed between a pair ofspaced yoke-like electrodes to slice tissue traversing the electrodesusing a translational movement that retracts the slicing blade into thebody while passing through the tissue. The electrodes may be angularlyoriented about the elongated axis of the body under manual control of anactuator mounted at the proximal end of the body for angular andtranslational movements linked to the electrodes and slicing blademounted at the distal end of the body.

In another embodiment of the invention, a tissue-shearing blade ismounted on the transparent tissue-dissecting tip to facilitatetransecting tissue within the endoscopic field of visualization. One ormore of the embodiments of the present invention may be incorporatedinto and form an integral part of more comprehensive surgical apparatus,for example, as illustrated and described with reference FIGS. 8 and 9of pending application Ser. No. 10/054,477, entitled “Vessel HarvestingApparatus and Method”, filed on Jan. 18, 2002 by M. Stewart et al.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of one embodiment of the tissuetransector according to the present invention.

FIGS. 2 a and 2 b are end views of the tissue transector of FIG. 1.

FIG. 2 c is a perspective view of an alternative configuration of ablade for the embodiment of FIG. 1.

FIG. 2 d is a partial side sectional view of another embodiment of atissue transector according to the present invention.

FIG. 3 a is an exploded perspective view of a manual manipulator for thetransector of FIG. 1.

FIG. 3 b is an end view of the manipulator of FIG. 3 a illustrating themechanical characteristics thereof.

FIG. 3 c is a perspective view of one embodiment of a manual manipulatorfor the transector of FIG. 1.

FIG. 4 is a plan view of an embodiment of a manual manipulator for thetransector of FIG. 1.

FIGS. 5 a and 5 b are partial side and top views, respectively, ofanother embodiment of the present invention.

FIGS. 5 c and 5 d are partial sectional views of a structure formanipulating the transecting blade according to the present invention.

FIGS. 5 e, 5 f and 5 g are, respectively, partial side, end andperspective views of another embodiment of the present invention.

FIG. 6 is a partial sectional view of a tissue-dissecting transparenttip including another embodiment of a tissue transector according to thepresent invention.

FIG. 7 is a partial sectional view of a transparent tissue-dissectingtip on the distal end of a cannula that includes a lumen therethroughfor delivering pressurized fluid in accordance with the presentinvention.

FIG. 8 is a pictorial end view of a cannula including a lumentherethrough for delivery of fluid under pressure to thetissue-dissecting tip.

FIG. 9 is a partial perspective view of the cannula of FIG. 7illustrating the orientation of multiple lumens within the cannula.

FIGS. 10 a and 10 b comprise a flow chart illustrating a methodembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the exploded perspective view of FIG. 1, there is shownthe distal end of an elongated hollow support body 12 for the tissueelectrocauterizer and transector in accordance with one embodiment of anend effector of the present invention. An electrically-insulating hub 13formed of a polymer such as polycarbonate is disposed to fit within theinternal bore of the body 12, up to the axial extent of a flange 21surrounding the perimeter of the hub 13 at about the mid-length thereof.The hub 13 includes three spaced, parallel slots 14 that are verticallyaligned to receive therein a tissue-slicing blade 16 in the central slotand two yoke-shaped planar electrodes 11 in the slots 14 disposed onopposite sides of the central slot. Each of the electrodes 11 includesan axially-aligned recess or slot 15 having a width that may taperinwardly 30 from a forward edge of the electrode, as shown in FIGS. 2 a,2 b, or that may be substantially uniform in width along the lengththereof. Each of the electrodes has a rearward portion 22 that isintegral with the forward yoke-shaped portion, and that fits within thecorresponding slot 14 of the hub 13 for holding the electrode firmlytherein with the hub 13 positioned within the bore of the electricallyinsulating distal end of body 12. The base or root 32 of the slot 15extends forward of the adjacent hub to promote electrical contactthereat with vessels of smallest diameter received into the slots 15.Each electrode 11 includes a connector tab 23 for attachment thereto ofan electrical conductor (not shown) for supplying electrocautery signalthereto, as later described herein, with common polarity oriented inspaced planes that are substantially normal to a vessel disposed betweenslots 15 in the pair of electrodes.

The insulating hub 13 also includes a forward jaw-like portion 24 thatsubstantially aligns with the lower branches of the yoke-shapedelectrodes 11, and that includes an axial slot therein that extends inalignment with the central slot 14 through the rearward portion of thehub 13. The base of the forward portion of the central slot may befitted with a strip 18 of metal or preferably Tecothane™ in the forwardportion 24 to serve as an anvil for the blade 16. The upper edges of theforward portion of the central slot include serrations orupwardly-oriented ‘teeth’ 19 to aid in holding tissue in position withinthe recesses 15 of the adjacent electrodes 11 during tissue-cuttingoperation. The ‘teeth’ 19 may protrude slightly into the width of therecesses 15 in the adjacent electrodes 11 to facilitate holding tissuebeing cauterized or cut.

Specifically, tissue disposed within the recess 15 of the electrodes maybe electrocauterized, as described later herein, and transected by theslicing movement of the blade 16 that translates and elevates within thecentral slot 14 in hub 13. The blade 16 is securely attached to anactuating rod 20 that controls simultaneous elevation and translation ofthe blade 16 within the central slot 14. The actuator rod 20 includes aresilient bend 25 proximal to the attachment of the blade 16 to the rod20 for resiliently biasing the top edge 17, 27 of the rear portion ofthe blade against the top edge of the bore in tube 12 at the distal endthereof. A ferrule or ring 26 of wear-resistant material such as metalor dense polymer may be fitted at the distal end of tube 12 to inhibitwear during sliding contact with the top edge 17, 27 of the blade 16.The ring 26 may be split 28 to provide variable spacing and resilientforce of the blade 16 against the anvil 18. Thus, forward extension ofthe blade 16 configures the assembly in an ‘open’ position relative tothe anvil 18 at the base of the central slot 14. As the rod 20 isretracted proximally within the bore of body 12, the upper edge 17, 27of the blade 16 is engaged with the distal upper edge of the body 12 andring 26. Additionally, the inclined portion 17 of the upper edge engagesthe distal upper, edge of the body 12 and ring 26 to reduce theelevation of the cutting edge of blade 16 relative to the anvil 18toward a ‘closed’ configuration. Thus, translational or axial movementof the rod 20 in the proximal direction produces a compound slicing andclosing movement of the blade 16 within the central slot relative to theforward portion 24 of the hub 13 that supports the anvil 18 for blade16. Tissue disposed within the recesses 15 of the electrodes above theserrations 19 is thus transected in a smooth, slicing movement of theblade 16 as the rod 20 is selectively moved proximally, in the manner asdescribed herein. The resilient biasing force provided by the ring 26 inthe direction to urge the blade 16 into the anvil 24 may be altered bymodifying the width or thickness or material of the ring in knownmanner, or by altering the angular orientation of the split 28 about theaxis of the body 12.

Referring now to FIGS. 2 a and 2 b, there are shown end views of thetransector of FIG. 1, with illustrative engagements of the yoke-likeelectrodes 11 and a tissue structure such as a blood vessel 29.Electrocauterization may be achieved by engaging the tissue structure 29within the recesses or slots 15 of the yoke-shaped electrodes 11, andenergizing the electrodes, for example, in the bipolar manner ofopposite polarities of direct current or instantaneous polarities ofalternating current, as shown. The yoke-shaped electrodes 11 facilitateestablishing good electrical contact with the tissue structure 29,despite relative orientations thereof such as in diagonal traversalbetween upper tine of one yoke and lower tine of the other yoke, asshown in FIG. 2 a, or in lateral traversal between corresponding tinesof the two yokes, as shown in FIG. 2 b, or in maximum insertion to theroot or base of slots 15. Of course, the electrodes 11 may also beenergized in unipolar manner (of one/same polarity) relative to apatient's grounded body, or relative to a grounded blade 15 brought intocontact with a tissue structure 29, in the manner as previouslydescribed herein.

Following electrocauterization of a tissue structure 29, the actuatorrod 20 is tensioned proximally to retract the blade 16 into the borewithin the body 12, and simultaneously to advance the cutting edge ofthe blade 16 toward the ‘closed’ configuration against the anvil 18, aspreviously described. These movements promote smooth slicing actionthrough the tissue structure 29 that tends to be further drawn into therecesses 15 in the spaced electrodes 11 and down onto the serrations 19on the upper edges of the forward portion 24 of the hub 13 disposedbetween the electrodes 11 for secure anchoring of the tissue structure29 during transection in this manner. Additionally, tissue structures 29of larger sectional dimensions may be wedged into tapered recesses 15 inthe yoke-like electrodes 11 for enhanced electrical connection theretoduring electrocauterization, and for improved anchoring duringtransection.

Alternatively, the blade 16 may be positioned substantially asillustrated in FIGS. 2 a and 2 b with the cutting edge of the blade 16angled downwardly and inwardly across the dimensions of the slots 15 tofacilitate slicing sheet-like tissue structures by simply advancing thestructure through the sheet-like tissue, without moving the bladebetween open and closed configurations. Alternatively, as illustrated inthe perspective view of FIG. 2 c, a tissue-cutting blade 9 may includean angled or ‘hook’-shaped sharpened edge 10 that may be retracted in aproximal direction to anchor a target vessel within the slots 15 inelectrodes 11, and to sever the vessel during translational, retractingmovement relative to the electrodes 11. A camming upper edge 8 of theblade 9 may curve upwardly from the rearward or proximal end of theblade 9 to facilitate camming action against a reference edge such asring 26 and to increase the upward movement into the ‘open’configuration via reduced translational movement.

As illustrated in the partial side sectional view of FIG. 2 d, the upperand lower tines of each of the electrodes 11 may be shapedasymmetrically, with longer, broader tines 11 a adjacently arranged anddisposed to confine a blade 16 a therebetween. The blade 16 a ispivotally mounted to rotate about an anchored pivot 42 in response totranslational movement of the actuator rod 20 that is linked thereto.The slots 15 in the electrodes may taper to a cusp or apex 45 to assurewedged engagement of a target vessel within the transversely-alignedslots 15 for promoting good electrical contact with the vessel.

In accordance with an embodiment of the present invention, the elongatedhollow support body 12 (or the hub 13 alone) may be angularly orientedover a range of angles about the axis of the elongated body tofacilitate easy alignment and engagement of the recesses 15 in theelectrodes 11 with the random orientations of tissue structures 29encountered during a surgical procedure. Specifically, as illustratedpictorially in FIGS. 3 a, 3 b, a finger-engageable control element 31 ismounted for rotation about an axis 36 aligned with the elongated axis ofthe body 13, and is mechanically linked to a connecting member 34 thatis mounted for rotation about an axis 35 at a shorter radius to the link33 than the radius of the control element 31 to its rotational axis 36.The link 33 includes a slot 37 in one of the control element 31 andconnecting member 34 in which a pin of the link 33 attached to the otherof the control element 31 and connecting member 34 may slide to take upthe differential variation in distances to the respective rotationalaxes 35, 36 as the control element 31 and connecting member 34 rotate inresponse to manual movement of the control element 31. In this way, theconnecting member 34 attached to the body 12 (or to the hub 13 alone)may rotate through a greater range of angles, α, for a smaller range ofangular movement, β, of the control element 31.

In addition, the control element 31 may also control deployment andretraction of the hub 13 and electrodes 11 and blade 16 for convenientmanual operation from the proximal end of the body 12.

In one embodiment, as illustrated in the perspective view of FIG. 3 c,the manual control element may include a first member 39 that is mountedto slide fore and aft along the longitudinal axis of a proximal handle40 and that is coupled to the body 12 for selectively advancing andretracting the body relative to the handle 40. The manual controlelement may also include a second member 44 that is mounted forlongitudinal movement within an elongated longitudinal slot 46 in thefirst member, and that is coupled to the rod 20 for selectivelyadvancing and retracting the rod 20 and attached blade 16 relative tothe body 12 and electrodes 11. Thus, the electrodes 11 and blade 16 maybe selectively advanced, with blade 16 in the open position, as thesecond member 44 is advanced distally to the extent of the slot 46.Proximal movement of the second member 44 within the slot 46 actuatesthe blade 16 into the closed position across the transverse spacing ofthe aligned slots 15 in the electrodes 11 (as to sever tissue disposedtherein), in the manner as previously described herein. Then, continuousproximal movement of the second member 44 against the proximal limit ofthe slot 46 also slides the first member 39 proximally to facilitateretraction of the electrodes 11 during one continuous movement of thesecond member 44 over a length of travel in excess of the length of slot46.

Referring now to the plan view of FIG. 4, there is shown one embodimentof the present invention including a control element 31 disposed torotate about a barrel segment of a proximal handle, and to translatealong slot 38 in the barrel for deploying and retracting the electrodes11 and blade 16 in a manner as previously described herein.

Referring now to FIGS. 5 a, 5 b, there are shown partial side and topviews, respectively, of another embodiment of an end effector accordingto the present invention in which each of a pair of electrodes 52, 54for electrocauterizing a tissue structure such as a blood vesselprotrude from an insulative hub 13 and retain common polarity in planessubstantially aligned with the vessel. One 52 of a pair of wire loopsthat form the electrodes 52, 54 is assembled through the hub 13 at thedistal end of the elongated supporting body 12 to cross through theother 54 of the pair of wire loops in order to form a root or base 53 ofconverging electrode planes that thereby assure electrical contacts to avessel of substantially any dimension disposed between the pairs of loopelectrodes 52, 54. A hook-shaped blade 55 is disposed to translatelongitudinally and laterally within a plane substantially normal to theplanes of the electrodes 52, 54 in response to the camming edge 56 ofthe blade being advanced or retracted relative to a reference surface,in the manner as previously described herein. As illustrated in thepartial top view of FIG. 5 b, the blade 55 is disposed within, andspaced away from the wire loops that form the electrodes 52, 54. Thisconfiguration of the blade 55 and electrodes 52, 54 avoids shortcircuiting of the electrodes 52, 54 that may be energized by appliedbipolar electrocauterizing signals, and also establishes the conductiveblade 55 as an additional electrode for alternative grounding ormonopolar or bipolar electrocautery operation.

Referring now to the partial side sectional views of FIGS. 5 c and 5 d,there is shown one embodiment of the present invention for manipulatinga cutting blade 9, 16, 55 between open and closed configurations inresponse to translational movement of the attached actuating rod 20.Specifically, the rod 20 includes a resilient bend 25 that is displacedproximally from the blade 9, 16, 55, and that straightens out to reducethe elevation of the blade as the rod is drawn through a close-fittinglumen 57 within the hub 13 or supporting body 12. The resulting combineddownward and retracting movement of the blade 9, 16, 55 greatlyfacilitates transection of a target tissue structure that is confinedbeneath the descending and retracting blade.

Referring now to the partial side, end and perspective views of FIGS. 5e, 5 f, 5 g, there is shown another embodiment of an end effector inaccordance with the present invention. In this embodiment, the endeffector is disposed at the distal end of an elongated support body 12and includes a blade and electrode structure for electro-cauterizing andtransecting tissue structures such as blood vessels. The blade 58 ismounted for translational movement relative to the support body 12 inresponse to manual manipulation of one or more manual control elements59, 60 that are mounted on a handle 67 at the proximal end of thesupport body 12, and that are linked to the blade and electrodestructure at the distal end of the body 12. The blade 58 includes aproximal cutting edge 70 that is oriented substantially normally to thedirection of translational movement. The blade 58 includes a generallytapered blade guard 72 that protrudes distally from the distal edge ofthe blade 58 to serve as a manual probe and guide for manipulating theend effector through tissue during positioning of the end effectorrelative to a target vessel.

A loop electrode 74 surrounds and is spaced from the blade 58, and isdisposed within a plane that is skewed to converge proximally with asupporting base 76 of the blade 58. The blade 58 and loop electrode 74are supported within respective channels within the hub 13 at the distalend of the support body 12. A resilient anvil 75, for example, formed ofsilicone rubber is disposed against the distal end of the hub 13 toreceive the cutting edge 70 at the proximal extent of its translationalmovement. In this configuration, a tissue structure such as a bloodvessel may be confined between the loop electrode 74 and the base 76 ofthe blade-electrode 58, between the cutting edge 70 and the resilientanvil 75. Bipolar electrical signal supplied to the conductive blade 58and electrode 74 via electrical conductors 77 within the body 12 andconnector 78 thus electrocauterizes the confined tissue prior to beingtransected by movement of the cutting edge 70 proximally toward theresilient anvil 75. Additionally, the loop electrode 74 may include aresilient bend that can be drawn through its supporting channels withinthe hub 13, in a manner as previously described herein with reference toFIGS. 1, 5 c, 5 d, to effect compression of confined tissue against thebase 76 of the blade 58. Independent links between the blade 58 and oneof the control elements 59, 60, and between the electrode 74 and theother of the control elements 59, 60 greatly facilitate manipulation ofthe end effector to capture, confine, cauterize and cut a target tissuestructure.

Referring now to the partial sectional view of FIG. 6, there is shown asectional view of another embodiment of a tissue transector according tothe present invention including a section through a transparenttissue-dissecting tip 41 that is attached to the distal end of anendoscopic cannula 43. An endoscope 64 within a lumen in the cannula 43is substantially aligned with the apex 42 of the tapered tip 41 toestablish a field of view through the tip 41 with a minimum of visualdistortion and obstruction within the field of view.

In accordance with the illustrated embodiment of the present invention,a tissue transector 47, 48 is disposed within a tapered wall of the tip41 to facilitate selectively transecting tissue structures such as bloodvessels that may be encountered along a course of tissue dissection.Specifically, one cutting blade 47 may be firmly attached to the tip 41,with a cutting edge thereof substantially flush with the tapered outerwall and oriented toward the apex 45 a of the tip. Another cutting blade48 may be pivotally attached to the fixed blade 47 for scissor-likerelative movement of the blades about a fixed pivot 50 in response totranslational movements of the actuator rod 49 that is linked to themoveable blade 48. A manually actuatable control element (not shown)mounted near a proximal end of the cannula 43 and arranged inconventional manner to translate the actuator rod 49 to implement thescissor-like shearing action of the blades 47, 48 under manual control.

In operation, the pair of blades 47, 48 may be positioned together inclosed configuration substantially flush with the outer surface of thetip 41. A slit 51 within the wall of the tip 41 facilitates recessingthe blades 47, 48 in the closed configuration to be unobstructive duringtissue dissection as the tip is advanced through tissue. Alternatively,an integral recess within the outer wall of the tip may be provided topreserve the sealing properties of the tapered tip 41 relative to thedistal end of the cannula 43, and to provide a receptacle within whichthe blades 47, 48 may be retained in unobstructive closed configuration,until required for selective transection of tissue structuresencountered along a tissue-dissection course. Then, a manual actuator(not shown) positioned near a proximal end of the cannula 43 and linkedto the rod 49 may translate the rod 49 forward to rotate the blade intothe ‘open’ configuration, as shown. The cannula 43, tip 41 and blades47, 48 may then be positioned with a tissue structure such as a bloodvessel disposed between the blades 47, 48. Tensioning the rod 49 via themanual actuator (not shown) near the proximal end of the cannula 43 thusrotates the blade 48 about the pivot 50 in scissor-like movement totransect the tissue structure disposed between the blades. Of course,the blades 47, 48 may also support electrodes near the cutting edgesthereof in conventional manner for use in bipolar electrocauterizationof tissue prior to transection.

Referring now to FIG. 7, there is shown a sectional view of anendoscopic cannula 61 having a tissue-dissecting transparent, taperedtip 63 attached to the distal end of the cannula 61, with the apex ofthe tapered walls substantially aligned with an endoscope 64 disposedwithin a lumen of the cannula 61. In accordance with the illustratedembodiment of the present invention, the tapered tip 63 is configured toprovide both tissue dissection and a convenient gas port forsimultaneous insufflation of an anatomical cavity formed in dissectedtissue. Specifically, the lumen of the cannula within which theendoscope 64 is fitted (or other lumen) serves as a gas passage forwardof the sliding seal 62 along the cannula between a gas-entry port 65near the proximal end of the cannula 61 and the tip 63 disposed over thedistal end of the cannula 61. The tip 63 is spaced away from the cannula61 by a plural number of radially-extending spacers 66 that are evenlyspaced around the perimeter of the cannula 61. The resultant spacingbetween the distal end of cannula 61 and inner walls of the tip 63provides an outlet port for gas under pressure to exit from thetransporting lumen within the cannula 61. In the illustrated embodiment,stand-off spacers 66 separate the inner walls of the tip 63 from theouter walls of the cannula to establish the gas outlet port. In anotherembodiment, for example, as illustrated in FIG. 6, a slit 51 through thetapered wall of the tip 41 also serves as an outlet port for gas underpressure to be supplied substantially at the remote surgical site wheretissue is being dissected. Positive gas pressure maintained from withina lumen of the cannula 43, 61 and from within the tissue-dissecting tip41, 63, inhibits incursion of tissue and fluids into the interior of thetip and cannula. And, insufflation gas released in this manner overcomescommon problems of trying to insufflate an extended anatomical space indissected tissue from the location of an access port near the initialincision.

Referring now to the pictorial end view of FIG. 8 and to the partialperspective view of FIG. 9, there is shown a portion of anotherembodiment of an endoscopic cannula 61 including a gas-inlet port 65disposed in fluid communication with a lumen 69 that traverses thelength of the cannula 61 between proximal and distal ends thereof. Theend view of FIG. 8 and the perspective view of FIG. 9 omit for clarityof illustration a proximal-end seal that closes off the proximal end ofthe lumen 69. Thus, gas supplied under pressure to the lumen 69 throughthe gas-inlet port 65 is transferred to the remote surgical site nearand around the distal end of the cannula for insufflating the anatomicalspace formed in dissected tissue. Other lumen 68, 71, 73 through thecannula facilitate sliding or rotational movements therein of controlrods and surgical instruments, such as an endoscope 64, or transector ofFIG. 1, or the like, during endoscopic surgical procedures of a type aspreviously described herein. Gas such as CO₂ under pressure may beconveniently supplied via flexible tubing 81 attached at one end to thegas-inlet port 65 and at an opposite end to a convenient fitting orconnector 82 such as a Luer-lock connector. Gas under pressure deliveredto the distal end of the cannula in this manner greatly facilitatesdilating tissue surrounding an anatomical space formed in tissue nearthe remote surgical site at which transection of vessels is performed inthe manner, for example, as described herein with reference to FIG. 1.In addition, suction can be applied to port 65 to remove fluid from thesurgical site.

Referring now to the flow chart of FIGS. 10 a and 10 b, there is shown amethod embodiment of the present invention used, for example, to isolatethe saphenous vein during a vascular surgical procedure. Specifically,an incision is formed 81 over the saphenous vein to expose the vein andinitiate tissue dissection through adherent tissue along the course ofthe vessel. An elongated cannula, having at least one lumen extendingtherein substantially between distal and proximal ends and configuredwith a transparent tissue-dissecting tip disposed over the distal end ofthe cannula, is inserted through the incision to bluntly dissect tissue83 away from the saphenous vein and from around side-branch vesselconnected to the vein. The tissue dissection is performed undervisualization by an endoscope that is positioned within the at least onelumen in the cannula to provide a field of view through the transparenttissue-dissecting tip. A portion of the length of the saphenous vein,and the connected side-branch vessels, are thus exposed and isolated 85within the anatomical space formed along the vein in the dissectedconnective tissue. Insufflation of the anatomical space may be performed87 during or following tissue dissection using gas under pressure thatmay be delivered in a manner as previously described herein to dilatethe tissue surrounding the anatomical space in order to expand theworking space around the saphenous vein. The endoscopic cannula is thenremoved from the anatomical space through the initial incision, and thedistal end is reconfigured 89 by removing the tissue-dissecting tip toexpose a plural number of lumens that extend within the cannula to thedistal end thereof. Alternatively, a cannula having a plural number oflumens extending therein to the distal end thereof, and not requiringreconfiguration by removal of a tissue-dissecting tip from the distalend, may also be used. The cannula thus configured includes a pluralnumber of lumens, for example, as described herein with reference toFIGS. 8 and 9, with an endoscope slidably supported in one lumen, andwith a transector such as described herein with reference to FIG. 1slidably supported within a lumen of the cannula near the endoscopelumen.

The cannula configured with an endoscope and tissue transectorextendable through the distal end of the cannula is inserted 91 throughthe initial incision into the anatomical space along the saphenous vein.A side-branch vessel within the anatomical space is selectively engaged93 with the transector, for example, with the vessel traversing theslots between yoke-like electrodes, substantially as described hereinwith reference to FIGS. 2 a and 2 b. The set of electrodes may beselectively rotated generally about the elongated axis of the supportingbody, for example, using a manual actuator as previously describedherein with reference to FIGS. 3 a, 3 b, 3 c and 4, in order to orientthe yoke-like electrodes to receive the side-branch vessel across therespective slots. The electrodes are bipolarly energized 95 to heat andcauterize the vessel in the region between electrodes, and thecauterized vessel is then severed 97 by the transector blade that isdisposed to slice the vessel intermediate the electrodes.

This procedure is used to cauterize and sever each side-branch vesselthat is encountered along the course of the portion of the saphenousvein that is isolated within the anatomical space of dissected tissue.After all such side-branch vessels are cauterized and transected 99, thetransector may be removed from within the anatomical space 101, and fromwithin the cannula. This facilitates introduction of a ligating andtransecting instrument, or instruments, through the cannula to ligateand transect the isolated saphenous vein in conventional manner forremoval from the anatomical space.

Therefore, the apparatus and methods for electrocauterizing andtransecting tissue in accordance with the present invention facilitatetissue dissection and electrocauterization and transection of tissue atremote surgical sites within tissue being dissected. An anatomical spaceformed in dissected tissue may be conveniently insufflated at the remotesurgical site by delivering gas under pressure to the distal end of acannula. Endoscopic visualization of tissue dissection at the remotesurgical site is greatly improved by providing insufflating gas underpressure through the tissue-dissecting tip. Such remote delivery ofinsufflating gas to the distal end of the cannula facilitates surgicalprocedures such as transecting vessels within an anatomical space indissected tissue.

1. Apparatus for surgically treating tissue, the apparatus comprising: apair of yoke-shaped electrically conductive members mounted in spacedsubstantially plane parallel array, with each member formed as asubstantially planar sheet including a slotted opening extendinginwardly from a forward edge thereof, and with the slotted openings ofthe members substantially transversely aligned to receive therein thetissue to be treated, each of the members including a conductive portiondisposed above the slotted opening and a conductive portion disposedbelow the slotted opening to configure each member as an electrodedisposed above and below the slotted opening and operable at one oropposite polarity; a cutter mounted intermediate the spaced members formovement in a plane parallel to and spaced from the members between anopen configuration in which the cutter is displaced from obstructingtransverse alignment of the slotted openings, and a closed configurationin which a cutting edge of the cutter passes through the transversealignment of the slotted openings for transversely severing tissuedisposed in the slotted openings and across the spacing of the members;and an actuator linked to the cutter for controlling movement thereof inthe plane spaced from the members between the open and closedconfigurations.
 2. The apparatus as in claim 1 including a mountingstructure disposed at the distal end of an elongated body to support themembers in spaced array with the slotted openings substantially alignedin a direction along an elongated axis of the body, the mountingstructure also supporting the cutter for movement intermediate themembers; and the actuator extends along the body toward a proximal endthereof; and further comprising: a manual manipulator mounted near theproximal end of the body and linked to the actuator for selectivelymoving the cutter between the open and closed configurations in responseto manual actuation of the manipulator.
 3. The apparatus according toclaim 2 in which the width of each of the slotted openings converginglytapers inwardly from the forward edge.
 4. Apparatus according to claim 2in which the anvil is interposed between the pair of members displacedfrom obstructing a transverse alignment of the slotted openings with thecutter disposed in the open configuration, the anvil extendingsubstantially to the forward edges of the members, with the cutting edgeof the cutter disposed to substantially engage the anvil in the closedconfiguration.
 5. The apparatus as in claim 4 in which the cutter isdisposed to move translationally within a plane parallel to the membersalong a direction aligned with the elongated axis of the body andlaterally toward an anvil disposed below the slotted openings duringtransition from the open configuration to the closed configuration. 6.The apparatus as in claim 5 in which the cutter includes a contouredsurface for engaging a reference surface to transform translationalmovement of the cutter into translational and lateral movement relativeto the anvil.
 7. The apparatus as in claim 6 in which the contouredsurface of the cutter includes an edge thereof proximally remote fromthe cutting edge disposed to engage the reference surface that is fixedrelative to the body for urging the cutting edge toward the anvil inresponse to translational motion of the cutter in a direction toward theproximal end of the body.
 8. The apparatus as in claim 6 in which thereference surface is disposed to resiliently bias the cutter toward theanvil in engagement with at least a portion of the contoured surface ofthe cutter.